1. Field of the Invention
This invention relates to a saw chain of pivotally interconnected links wherein the pivotal connections are headless fasteners.
2. Background of the Invention
Saw chain is typically constructed with alternating center links and side link pairs that are pivotally interconnected by rivets. The rivet holes of the center link are of a larger diameter than the rivet holes of the side links. The rivet is configured with a center section that fits the center link rivet hole and has end sections of reduced diameter &:o fit the rivet holes of the side links. The center section of the rivet has a width slightly greater than the width of the center link to prevent the side links from pinching against the center link. The end sections of the rivets protrude through the side links and a head is formed on each end of the rivet to prevent the side links (and center link sandwiched between the side links) from coming off the rivets. At least one of the heads has to be formed after assembly, e.g. by spinning, which is a relatively expensive operation.
The protruding heads of the rivets at each side of the chain adds undesirable width to the chain. This requires the cutters of the chain to produce a kerf sufficiently wide to prevent the heads of the rivets protruding from each side of the chain from binding or rubbing against the side of the kerf produced.
Saw chain used for cutting aggregate material (rock and masonry) is different than the typical saw chain. The cutting element which is often a diamond impregnated steel block bridges across and is rigidly attached to the two side links of select pairs of side links. The block width extends beyond the sides of the side links as necessary to encompass the rivet heads. The diamond impregnated block is expensive and the added width of the rivet heads adds undesirable extra cost to the cost of the chain.
It is an object of the present invention to provide a headless fastener to replace the headed rivet and particularly as concerns saw chain for cutting aggregate materials.